/usr/lib/ghc-doc/hoogle/libghc-opengl-doc.txt is in libghc-opengl-doc 3.0.1.0-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-opengl-doc/html/OpenGL.txt